1. Field of the Invention
The present invention relates to an apparatus for automatically and incrementally feeding a continuous fan-folded document having interconnected segments, such as a continuous computer print-out, over a bed plate of an electrostatic flash illumination photocopier. The apparatus also correctly positions each document segment on the bed plate for copying.
2. Description of the Prior Art
For convenience, information tabulated by computer is frequently printed on a continuous form having sequentially arranged segments with the leading edge of each segment separably attached to the trailing edge of the preceding segment. Ordinarily, such continuous forms have a series of drive holes along each edge so that the entire document can be easily handled and driven by machines equipped with a conventional sprocket or tractor drive mechanism.
Because computer tabulated information is often widely distributed, it is desirable to quickly and efficiently provide duplicate copies of fan-folded documents on which the information is printed. Various known methods of form reproduction have certain drawbacks, however. For example, presently available high speed computer printers can make multiple carbon copies but this capability is limited. Generally, the quality of the carbon copies decreases as the number of carbon copies made is increased.
Alternatively, each segment of the continuous document may be separated from the remainder to be photocopied or otherwise duplicated with known office reproducing equipment. However, the time consumed by such a process makes it prohibitively expensive to produce large numbers of copies of long documents. Moreover, once separated, segments of the original document may be lost or incorrectly rearranged making it difficult to later produce additional accurate copies.
Proposals for apparatus which automatically feed a fan-folded document through a photocopier have been made. For example, U.S. Pat. No. 3,446,554, issued to Hitchcock et al, discloses a large complex apparatus for use with a scan-type photocopier which holds only a portion of the document being scanned in stationary position against the photocopier platen or bed plate. A loop is formed between two rollers from the remainder of the document. The rollers advance the loop above the platen while holding the scanned document portion in its stationary position. The Hitchcock et al apparatus is carefully synchronized with the scan-type photocopier so that the portion of the document being scanned does not move during the copying process. Efficiency is achieved by simultaneously advancing one portion of the document while another portion is being copied rather than waiting for the entire document to be scanned and copied before it is advanced.
U.S. Pat. No. 3,804,514, issued to Jasinski, is directed to a dual function document stop for a scan-type photoconductor, but also discloses a pair of feed tractors which intermittently draw a fan-folded document across the photocopier platen. However, no detailed description of the operation of the feed tractors is disclosed in the Jasinski patent.
Neither of the devices disclosed in either the Hitchcock et al and Jasinski patents take advantage of the capabilities of a flash illumination photocopier to achieve high speed reproduction.
U.S. Pat. No. 3,255,662, issued to Call, discloses a machine for microfilming fan-folded documents which includes an automatic document feed mechanism. Linear speeds of both the documennt and the microfilm on which it is projected are synchronized to attain the proper reduction ration of document size to filmed image. However, the document is not incrementally fed through the machine for individual exposure of each document segment.
It is preferable to automatically feed the entire document, intact, through the reproducing equipment used to make the copies. In this manner, the integrity of the original document can be maintained for later copying if necessary, and the time required to complete the reproduction process can be greatly reduced.
The efficiency of such a copy production process may be further enhanced by use of a high speed, flash illumination or full frame exposure-type photocopier which exposes a complete document at one time for projection on a copy sheet. This type of photocopier is generally faster than conventional scan-type machines which illuminate and project successive, incremental areas of the document being copied in a copy sheet.
A flash illumination photocopier, of the type with which the apparatus of the present invention can be used, is disclosed in U.S. Pat. No. 3,738,743, issued to Hoffman et al, assigned to the assignee of the present invention.